Sergei Lebedev 36f6b52e42 Upgrade most .py sources to 3.9
This commit was generated by running

    pyupgrade --py39-plus --keep-percent-format {jax,tests,jaxlib,examples,benchmarks}/**/*.py
2023-12-08 12:23:15 +00:00
..
2023-12-08 12:23:15 +00:00